This invention is an improvement in wastewater treatment plants or systems, particularly home aeration systems, which experience periodic process upsets of varying load conditions which reduce efficiency. Heretofore the assignee of the present invention patented a wastewater treatment system under U.S. Pat. No. 5,413,706 issued on May 9, 1995 which particularly provided novel flow equalization ports so as to maintain efficiency of the wastewater treatment system even during process upsets or varying load conditions.
In the latter patent the wastewater treatment mechanism 250 of FIGS. 10 through 17 is most representative of prior art and reflects flow equalization provided by three diametrically opposite pairs of vertically spaced flow equalization ports defined by (i) a lowermost diametrically opposite pair of design flow equalization ports, thereabove (ii) a pair of diametrically opposite sustained flow equalization ports, and (iii) a pair of uppermost diametrically opposite peak flow equalization ports. Two or more of the latter pairs of flow equalization ports build up a static head of the wastewater on the upstream side of the wastewater treatment mechanism when the incoming wastewater flow rate exceeds the ability of the flow equalization ports to pass the wastewater at the given static head. The elevation of the lowest pair of diametrically opposite design flow equalization ports determines the normal operating wastewater level of the entire wastewater plant. The second next upper pair of diametrically opposite sustained flow equalization ports are located approximately 3½″ above the first diametrically opposite design flow equalization ports and come into play as the induced stream static head continues to increase as liquid level rises upstream. The higher the hydraulic head, the greater the pressure and, therefore, the more water which will proportionately flow out of the lower pair of design flow equalization ports until the next upper pair of sustained flow equalization ports come into operation. In this manner the demand rate flow is achieved at minimal wastewater level fluctuation and minimum hydraulic currents. Finally, should prolonged and excessive incoming wastewater flow exceed the ability of both lower levels of flow equalization ports to pass the wastewater, the pair of uppermost diametrically opposite large size peak flow equalization ports become effective to pass the remaining flow. Over many years the latter wastewater flow equalization mechanism has assured efficient operation, particularly with respect to installation as part of a typical residential/home wastewater aeration system.
The assignee's U.S. Pat. No. 5,413,706 was designed to afford optimum flow equalization for a wastewater treatment plant receiving flow according to a pattern devised by NSF International which was industry developed and accepted to represent a “typical” residential wastewater flow pattern. Most of the data used to derive this wastewater flow pattern came from studies of flow patterns of municipal collecting systems receiving residential wastewater. As such, this pattern represents collective flows, in toto, from a number of residences and small commercial installations. However, each installation has its own unique individual flow pattern based upon a variety of factors. These factors are made up of an infinite number of variables including the number of residents or visitors, the number of plumbing fixtures, lifestyles, etc. However, once these factors are established for each installation, they are likely to stay relatively stable over a time and are generally repeatable. Therefore, having this ability to adapt the flow equalization equipment to the individual characteristics of each wastewater flow pattern allows optimum flow equalization for each unique installation. Such has been provided by the assignee of the latter patent over years of its manufacture and installation of the subject matter thereof.